The present disclosure relates to semiconductor device manufacturing, and more particularly to a method of removing multiple, i.e., two or more, semiconductor device layers from an underlying base substrate.
Devices that can be produced in thin-film form have three clear advantages over their bulk counterparts. First, by virtue of less material used, thin-film devices ameliorate the materials cost associated with device production. Second, low device weight is a definite advantage that motivates industrial-level effort for a wide range of thin-film applications. Third, if dimensions are small enough, devices can exhibit mechanical flexibility in their thin-film form. Furthermore, if a device layer is removed from a substrate that can be re-used, additional fabrication cost reduction can be achieved.
Efforts to (i) create thin-film substrates from bulk materials (i.e., semiconductors) and (ii) form thin-film device layers by removing device layers from an the underlying bulk substrates on which they were formed are ongoing.
One way to form a thin film device is to release a semiconductor device layer from a base substrate utilizing an epitaxial lift off (ELO) process. In a conventional ELO process for III-V compound semiconductor materials, an AlAs layer is inserted between an III-V compound semiconductor material and an overlying semiconductor device layer. The resultant structure is then subjected to etching in HF. After the etch, the semiconductor device layer is released from the III-V compound semiconductor material.
The conventional ELO process mentioned above can only release a single III-V compound semiconductor material after the etching. As such, the throughput of a conventional ELO process is low.
There is thus a need to provide a method which increases the yield of a conventional ELO process such that a plurality of semiconductor device layers, such as III-V compound semiconductor material layers, can be released from atop a single base substrate.